3 Commits

Author	SHA1	Message	Date
Lucas CHOLLET	05c8ad4e91	LibGfx/JPEG: Write quantization tables in the zigzag ordering ... This is clearly something I missed during the first implementation. The specification is crystal clear about it: "The quantization elements shall be specified in zig-zag scan order." This patch fixes the weird behavior we had when using the quantization table.	2023-07-04 00:01:06 +02:00
Lucas CHOLLET	cc1bd2d2d9	LibGfx/JPEG: Use a look-up table for cosine values ... This solution is a middle ground between re-computing `cos` every time and a much more mathematically complicated approach (as we have in the decoder). While still being far from optimal it already gives us a 10x improvement, not that bad :^) Co-authored-by: Tim Flynn <trflynn89@pm.me>	2023-06-25 00:22:21 +02:00
Lucas CHOLLET	226b214142	LibGfx/JPEG: Add a JPEG encoder :^) ... This encoder is very naive as it only output SOF0 images and uses pre-defined Huffman tables. There is also a small bug with quantization which make using it over-degrade the quality.	2023-06-22 21:13:04 +02:00